Re: Lathe & Mill

[Jon Elson <elson-at-pico-systems.com>]

Richard wrote:

>Hello Jon,
>
>Wednesday, November 6, 2002, 5:46:23 PM, you wrote:
>
>JE> Yes, this is easy!  I often do this when testing, running different 
>JE> setups on the same
>JE> computer.  it only takes seconds to switch.
>
>That's good news, at least. As for getting used to a new OS, if
>I have to do it then I'll give it a go, but you know what they
>say about old dogs and new tricks.
>  
>
Yes, I was the same way, and a Unix hater from WAY back!  But, they've 
made it a lot easier
with management tools, automatic install from CD, etc.  I'm finally a 
convert, and do all my
email, web browsing, software development, etc. on Linux.  Kind of nice 
to have the machine
stay up for months at a time, laugh at the viruses, and so on.

>I just looked at the emc project page at Sourceforge and it says
>:
>
>"....It runs in real-time under Linux with the NMT rtlinux patch,
>and in nonrealtime under Solaris, and WindowsNT."
>
>Hmmm... has anybody built a working binary for NT, or knows what
>is needed to do so?
>
>  
>
I don't know who wrote that, but it is wrong.  Yes, a version of EMC ran 
under Solaris about
6 years ago.  I don't think anyone could get it to run again on a Sun in 
less than a month.  (I could
be wrong, NIST may have kept this option available, but I doubt it.)  As 
for NT, they experimented
with 2 real-time options for NT about 4 years ago, and the results were 
abominable.  They showed
that while 99+% of the servo cycles were within a few % of desired, 
there were delays up to 3 seconds
that happened once in a while.  This is totally unacceptable for machine 
tool motion control.
I find a cycle-time variation of much less than 1%, and have a 10 mS 
watchdog that has never
fired.  So, I don't think EMC ever actually ran on NT, and certainly 
never moved iron on it.
There was a SIMULATOR for the screen that ran on various Windows 
systems, but it was
just a mock-up.

Pieces of EMC were used as a base for Art Fenerty's Master CNC and 
Mach-1, which does run on
some Windows systems, but it is NOT EMC.

Jon